Norman Part III: Our bull calf and his freemartin twin sister

Mama Trudy and Norman

Mama Trudy and baby Norman

Recently I’ve written about a set of twins born at our ranch. The mother cow unfortunately promptly rejected the bull calf in favor of the heifer calf such that Trudy and I soon became surrogate parents to the bull calf. We have been bottle feeding him twice a day. Well at least we don’t have to throw him over our shoulders and burp him!

While cattle twins are rare, We’ve learned the concept of freemartinism in cattle. This occurs when a male calf (Norman in our case) and his female twin are born. The heifer usually has an abnormal reproductive tract. Her abnormality occurs due to the presence of male hormones in the bloodstream in utero that prevents normal development of the ovaries and/or other aspects of her reproductive tract.

The freemartin becomes an infertile cow with masculinized behavior (someone else will have to share exactly what this behavior looks like as I haven’t noticed any unusual spitting or scratching (thank you Ann Richards for the quote). A freemartin occasionally occurs in sheep, goats, and pigs.

The Roman writer Varro described freemartins and referred to them as “taura”. John Hunter, an 18th century physician, determined a freemartin always has a male twin. Talk about creating sibling grudges!

The question arises whether this condition might occur in human twins as this has been claimed in folklore. This belief was perpetuated for generations and was mentioned in the early writings of Bede. No good support exist for freemartins in human twins to the best of my knowledge. If others know differently please share your thoughts and level of support for this.

Norman and a big friend

Norman and a big friend


Am pleased to share with you that Norman is growing and appears healthy. Another mama cow has allowed Norman periodically to nurse. Likewise his sister does well and continues to enjoy the mothering offered her by her biological mother. As for Norman he spends time in the nursery with the other calves during the day, scampers toward Trudy and me when we approach him, and like his ears and neck scratched.

Norman’s twin (the freemartin) is destined to become a beef calf rather than for breeding purposes. If I don’t watch it, Norman may, if Trudy has her way, end up as a big backyard pet.

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One thought on “Norman Part III: Our bull calf and his freemartin twin sister

  1. Madeline April 19, 2016 at 1:31 pm Reply

    I’m thinking . . . I might very well . . . well, probably would . . . end up voting with Trudy!

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